(19)
(11)EP 2 570 777 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
04.11.2020 Bulletin 2020/45

(21)Application number: 12184536.6

(22)Date of filing:  14.09.2012
(51)International Patent Classification (IPC): 
G01D 5/20(2006.01)
G06F 3/046(2006.01)
G06F 3/041(2006.01)

(54)

Sensing apparatus for measuring position of touch object by electromagnetic induction and method for controlling the same

Messgerät zum Messen der Position von Berührungsobjekten durch elektromagnetische Induktion und Verfahren zur Steuerung davon

Appareil de détection destiné à mesurer la position d'un objet tactile par induction électromagnétique et son procédé de commande


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 15.09.2011 KR 20110092968

(43)Date of publication of application:
20.03.2013 Bulletin 2013/12

(73)Proprietor: Samsung Electronics Co., Ltd.
Suwon-si, Gyeonggi-do, 443-742 (KR)

(72)Inventor:
  • Kim, Byung-Jik
    Suwon-si 443-742 Gyeonggi-do (KR)

(74)Representative: HGF 
1 City Walk
Leeds LS11 9DX
Leeds LS11 9DX (GB)


(56)References cited: : 
EP-A1- 0 694 863
JP-A- 2002 244 806
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    BACKGROUND OF THE INVENTION


    1. Field of the Invention



    [0001] The present invention relates generally to electromagnetic induction input technology, and more particularly, although not exclusively, to a sensing apparatus based on electromagnetic induction input technology, and a method for controlling the same.

    2. Description of the Related Art



    [0002] Along with the rapid growth of markets for smart phones and other touch screen devices, extensive research has recently been conducted on these technologies. A user can input a specific command to a smart phone or other touch screen device by selecting a specific position or icon on the display of the touch screen device with a user's body part (e.g. finger) or an Electromagnetic Induction (EI) pen.

    [0003] The selection through contact with a user's body part can be implemented by using capacitive touch screen technology. A capacitive touch screen typically includes transparent electrodes and condensers between the transparent electrodes. As the user touches the touch screen, the touch is sensed based on the resulting changed capacity of the condensers.

    [0004] However, it is difficult to provide precise input with capacitive type touch screens due to a relatively large contact area over which a user touches the touch screen with a body part. In contrast, EI touch screen technology offers the benefit of operation in response to a touch over a relatively small area with an EI pen.

    [0005] The EI scheme controls generation of an electromagnetic field by applying a voltage to a loop coil disposed on a Printed Circuit Board (PCB) and controls transfer of the electromagnetic field to an EI pen. The EI pen includes a condenser and a loop and emits the received electromagnetic field at a specific frequency. The electromagnetic field emitted from the EI pen is transferred to the loop coil of the PCB so that a position on the touch screen corresponding to the EI pen can be determined based on the electromagnetic field.

    [0006] Conventionally, in order to apply an electromagnetic field to an EI pen, current flows through all loop coils arranged on a PCB for EI. As a result, power consumption in the touch screen device is increased. Especially when a portable battery is used, such as in a mobile device, increased power consumption reduces battery life, which may have significant adverse effects on user convenience.

    [0007] Moreover, conventional EI technology requires a long time in order to sense input, due to each of the loop coils on the PCB being controlled to sense a change in the electromagnetic field received from the EI pen.

    [0008] EP 0694863 A1 relates to a method and device for detecting position without producing discrepancy caused by residual induction voltage of a resonant circuit.

    [0009] JP 2002244806 A relates to a pen-shaped coordinate indicator aimed at providing a slimmer constitution for indicating a position to be measured to a position detector.

    SUMMARY OF THE INVENTION



    [0010] It is an aim of the present invention to address, solve, mitigate or obviate, at least partly, at least one of the problems and/or disadvantages associated with the prior art. Certain embodiments aim to provide at least one of the advantages described below. Accordingly, the present invention provides an electromagnetic sensing apparatus according to claim 1.

    [0011] In accordance with another aspect of the present invention, a method for controlling an electromagnetic sensing apparatus is defined in claim 7.

    [0012] Other aspects, advantages, and features of the invention are defined in the dependent claims.

    [0013] Exemplary embodiments of the invention will become apparent to those skilled in the art from the following detailed description, taken in conjunction with the annexed drawings.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0014] The above and other aspects, and features and advantages of certain exemplary embodiments and aspects of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

    FIG. 1 is a conceptual diagram illustrating an electromagnetic sensing apparatus according to an embodiment of the present invention;

    FIG. 2A is a block diagram illustrating an electromagnetic sensing apparatus according to an embodiment of the present invention;

    FIG. 2B is a block diagram illustrating an electromagnetic sensing apparatus according to another embodiment of the present invention;

    FIG. 2C is a conceptual diagram illustrating an implementation of an electromagnetic sensing apparatus according to an embodiment of the present invention;

    FIGs. 3A, 3B and 3C are conceptual diagrams illustrating a method for detecting the coordinates of an Electromagnetic Induction (EI) pen according to an embodiment of the present invention;

    FIG. 4 is a flowchart illustrating a method for controlling an electromagnetic sensing apparatus according to an embodiment of the present invention;

    FIG. 5 is a flowchart illustrating a method for controlling an electromagnetic sensing apparatus according to another embodiment of the present invention; and

    FIG. 6 is a flowchart illustrating a method for controlling an electromagnetic sensing apparatus according to further another embodiment of the present invention.


    DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION



    [0015] Exemplary embodiments of the present invention are described as follows with reference to the attached drawings. This description is provided to assist in a comprehensive understanding of the present invention, as defined by the claims. The description includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the invention, which is solely defined by the appended claims.

    [0016] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention is provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims.

    [0017] In the drawings, like reference numerals denote the same or similar components. Detailed descriptions of generally known processes, functions, constructions and structures may be omitted for clarity and conciseness, and in order to avoid obscuring the subject matter of the present invention.

    [0018] Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of the words, for example "comprising" and "comprises", means "including but not limited to", and is not intended to (and does not) exclude other moieties, additives, components, integers or steps.

    [0019] Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, it is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise, and where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise. Thus, for example, reference to "an object" includes reference to one or more of such objects.

    [0020] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.

    [0021] It will be also be appreciated that, throughout the description and claims of this specification, language in the general form of "X for Y" (where Y is some action, activity or step and X is some means for carrying out that action, activity or step) encompasses means X adapted or arranged specifically, but not exclusively, to do Y.

    [0022] FIG. 1 is a conceptual diagram illustrating an electromagnetic sensing apparatus according to an embodiment of the present invention.

    [0023] Referring to FIG. 1, the electromagnetic sensing apparatus includes first and second sub-loop units 111 and 112 and a controller 120. The first and second sub-loop units 111 and 112 collectively form a loop unit.

    [0024] The first and second sub-loop units 111 and 112 are arranged so that they intersect perpendicularly. While a plurality of loops are shown in FIG. 1 as spaced from one another in each of the first and second sub-loop units 111 and 112, this configuration is merely provided as an example for clarity of description. The plurality of loops within each of the sub-loop units 111 and 112 may overlap each other in order to more accurately detect the coordinates of a pen in accordance with embodiments of the present invention.

    [0025] The plurality of loops in the first sub-loop unit 111 extends along a Y axis in order to sense X-axis coordinates. Meanwhile, the plurality of loops in the second sub-loop unit 112 extends along the X axis in order to sense Y-axis coordinates. Each of the plurality of loops in the first and second sub-loop units 111 and 112 senses an electromagnetic change and receives current.

    [0026] As described above, the configuration of the first and second sub-loop units 111 and 112 as sets of perpendicularly intersecting loops is merely provided as an example. Accordingly, the loops of the electromagnetic sensing apparatus may be divided into the first and second sub-loop units 111 and 112 in other various manners in alternative embodiments of the present invention.

    [0027] The first sub-loop unit 111 receives current from the controller 120, and the current flows through the loops of the first sub-loop unit 111 during a predetermined first time period. The first sub-loop unit 111 induces a predetermined electromagnetic field using the current and emits the electromagnetic field to the exterior of the device containing the electromagnetic sensing apparatus. The predetermined time period may be changed according to various conditions. Although, in the present example, the controller 120 applies current directly to each sub-loop unit, in other embodiments of the present invention, the controller 120 may instead control a power supply to the sub-loop units through an additional power supply.

    [0028] An EI pen close to the loop unit receives the induced electromagnetic field from the first sub-loop unit 111 and emits the induced electromagnetic field. Although the present example refers to an EI pen, other devices that receive and emit electromagnetic fields may be used in accordance with embodiments of the present invention. Herein, such devices are also referred to as touch objects.

    [0029] Meanwhile, the loops of the second sub-loop unit 112 are controlled to sense electromagnetic changes during the first time period. The loops of the second sub-loop unit 112 also sense changes in the electromagnetic field emitted from the EI pen. Because the EI pen can emit the electromagnetic field received from the first sub-loop unit 111, the electromagnetic field has been changed, and this electromagnetic change is sensed by the second sub-loop unit 112. The second sub-loop unit 112 senses electromagnetic changes and determines the Y-axis coordinate of the EI pen based on the magnitude of a maximum sensing signal sensed by a signal loop (referred to as a maximum signal loop) and the magnitudes of sensing signals from loops adjacent to the maximum signal loop.

    [0030] The second sub-loop unit 112 outputs all of sensing signals sensed by loops other than the maximum signal loop to the controller 120 and the controller 120 determines a peak based on the sensing signals from the plurality of loops. Therefore, the Y-axis coordinate of the EI pen can be determined more accurately.

    [0031] As described above, the controller 120 controls the first sub-loop unit 111 to receive current and controls the second sub-loop unit 112 to sense electromagnetic changes during the first time period.

    [0032] After the first time period, a second time period commences, during which the controller 120 controls the first sub-loop unit 111 to sense electromagnetic changes and controls the second sub-loop unit 112 to receive current. Herein, with respect to the terms "first time period" and "second time period" the terms first and second are used to distinguish between two alternating time periods, and there may be more than one occurrence of each of the first and second time periods during operations performed in certain exemplary embodiments of the present invention.

    [0033] Therefore, each loop of the second sub-loop unit 112 receives current and induces and emits an electromagnetic field using the current.

    [0034] The EI pen receives the electromagnetic field from each loop of the second sub-loop unit 112 and emits the received electromagnetic field.

    [0035] Each loop of the first sub-loop unit 111 senses a change in the electromagnetic field emitted from the EI pen. Thus, the X-axis coordinate of the EI pen is determined based on the magnitude of a maximum sensing signal sensed by a maximum signal loop and the magnitudes of sensing signals sensed by loops adjacent to the maximum signal loop.

    [0036] The first sub-loop unit 111 outputs all of sensing signals sensed by loops other than the maximum signal loop to the controller 120 and the controller 120 determines a peak based on the sensing signals and thus determines the X-axis coordinate of the EI pen.

    [0037] As described above, the controller 120 controls the second sub-loop unit 112 to receive current and controls the first sub-loop unit 111 to sense electromagnetic changes, during the second time period. Subsequently, the controller 120 repeats the operations set for the first and second time periods.

    [0038] More specifically, the controller 120 controls the first sub-loop unit 111 to alternate between current reception (i.e., emitting electromagnetic fields) and electromagnetic change sensing at a predetermined interval. The controller 120 controls the second sub-loop unit 112 to alternate between current reception and electromagnetic change sensing at the predetermined interval, alternately with the first sub-loop unit 111.

    [0039] Meanwhile, during the second time period the controller 120 may provide current flow only through a maximum sensing loop that has sensed a maximum sensing signal during the first time period in the second sub-loop unit, rather than through all loops of the second sub-loop unit 112.

    [0040] Switching between the first and second time periods is relatively fast, compared to displacement of the EI pen. Therefore, the EI pen may still be located in the vicinity of the maximum signal loop of the second sub-loop unit 112 even after the first time period.

    [0041] Accordingly, even though current flows only through the maximum signal loop of the second sub-loop unit 112 during the second time period, the EI pen receives and emits an electromagnetic field having a sufficient magnitude. As current flows only through one specific loop rather than through all loops, in contrast to conventional operations, power consumption is significantly reduced.

    [0042] As described above, after the second time period, the controller 120 repeats the operation set for the first time period. Notably, although current flows through all loops of the first sub-loop unit during the initial first time period, current may flow only through a maximum signal loop that has sensed a maximum sensing signal in the first sub-loop unit 111 during the second time period, during another first time period.

    [0043] As described above, the second time period switches to the first time period relatively fast, compared to the displacement of the EI pen. Since after the second time period, the EI pen may still be located in the vicinity of the maximum signal loop of the first sub-loop unit 111, the EI pen may receive an electromagnetic field having a sufficient magnitude in spite of current flowing only through the maximum signal loop of the first sub-loop unit 111 during the first time period.

    [0044] When the controller 120 subsequently provides current through the first or second sub-loop unit 111 or 112, the controller 120 may control current to flow only through the maximum signal loop of the previous time period in the first or second sub-loop unit 111 or 112. The controller 120 also controls the first and second sub-loop units 111 and 112 to alternately sense electromagnetic changes and thus determine the time-series coordinates of the EI pen.

    [0045] When the controller 120 controls the first or second sub-loop unit 111 or 112 to sense electromagnetic changes, the controller 120 may control the loops of the first or second sub-loop unit 111 or 112 to sense electromagnetic changes in groups. For example, if the first sub-loop unit 111 includes 258 loops and is controlled to sense electromagnetic changes, the controller 120 may group the loops of the first sub-loop unit 111 into six groups and may control each group to sense an electromagnetic change.

    [0046] Conventionally, an electromagnetic change is sensed on a per-loop basis. If time t is taken for one loop to sense an electromagnetic change, conventional operations may require 258t in order to sense electromagnetic changes in all loops. According to the present invention, because the controller 120 controls electromagnetic change sensing on a per-group basis, for example, through each of six groups. Consequently, electromagnetic changes can be sensed in a shorter time (i.e., 43t in the present example), and thus electromagnetic change sensing may be performed a plurality of times over a shorter period of time, thereby increasing the Signal to Noise Ratio (SNR) of a sensing signal.

    [0047] FIG. 2A is a block diagram illustrating an electromagnetic sensing apparatus according to an embodiment of the present invention.

    [0048] Referring to FIG. 2, the electromagnetic sensing apparatus includes a loop unit 210, a switch 220, a driver 230, a controller 240, and a signal processor 250.

    [0049] The loop unit 210 includes first and second sub-loop units 211 and 212. Each of the first and second sub-loop units 211 and 212 includes a plurality of loops. The loops of the first sub-loop unit 211 intersect perpendicularly with the loops of the second sub-loop unit 212, although other arrangements may be used in other alternative embodiments of the present invention.

    [0050] The switch 220 alternately outputs current received from the driver 230 to the first and second sub-loop units 211 and 212 during predetermined time periods under the control of the controller 240.

    [0051] During the first time period, the switch 220 switches to the first sub-loop unit 211, thus providing current through the first sub-loop unit 211. During the second time period, the switch 220 switches to the second sub-loop unit 212, thus providing current through the second sub-loop unit 212.

    [0052] The driver 230 generates current and outputs the current to the switch 220. Any of various devices that can store a predetermined power and generate current of a predetermined intensity may be used as the driver 230 according to embodiments of the present invention.

    [0053] Meanwhile, the switch 220 alternately switches to the first and second sub-loop units 211 and 212 during predetermined time periods under the control of the controller 240. Therefore, the first sub-loop unit 211 is connected to the signal processor 250 during the second time period and the second sub-loop unit 212 is connected to the signal processor 250 during the first time period. The signal processor 250 receives a sensing signal from the first sub-loop unit 211 during the second time period and from the second sub-loop unit 212 during the first time period. As described above, the switch 220 switches the loops of a sub-loop unit that senses electromagnetic changes to the signal processor 250 on a per-group basis.

    [0054] The signal processor 250 processes a received sensing signal to a form that can be processed in the controller 240.

    [0055] The controller 240 determines the coordinates of the EI pen based on sensing signals received from the loops of the sub-loop units 211 and 212 through the signal processor 250. The controller 240 may be implemented as a microprocessor, an Integrated Circuit (IC), a Central Processing Unit (CPU), a mini computer, etc.

    [0056] FIG. 2B is a block diagram illustrating an electromagnetic sensing apparatus according to another embodiment of the present invention.

    [0057] Referring to FIG. 2B, the electromagnetic sensing apparatus does not include the signal processor 250, in contrast to the electromagnetic sensing apparatus illustrated in FIG. 2A. While an analog signal is processed independently of the controller 240 in the electromagnetic sensing apparatus illustrated in FIG. 2A, an analog signal is processed in a controller 241 in the electromagnetic sensing apparatus illustrated in FIG. 2B.

    [0058] FIG. 2C is a conceptual diagram illustrating an implementation of an electromagnetic sensing apparatus according to an embodiment of the present invention.

    [0059] Referring to FIG. 2C, the controller 240 may be implemented on an IC arranged on a Printed Circuit Board (PCB), for example. Meanwhile, the controller 240 may be incorporated into a control chip of a portable phone including a CPU or the electronic sensing apparatus on a PCB. The controller 240 includes a connector unit 248. The connector unit 248 may include a signal transmitter for inputting/outputting input/output signals of a plurality of channels. The connector unit 248 may be configured into, for example, gold fingers. However, other configurations of the connector unit 248 may be used in other embodiments of the present invention. In addition, the number of the gold fingers illustrated in FIG. 2C is merely provided as an example.

    [0060] A loop unit 290 includes first and second sub-loop units 291 and 292, which may be connected to independent channels, that is, independent connectors.

    [0061] FIGs. 3A, 3B, and 3C are conceptual diagrams illustrating a method for detecting the coordinates of an EI pen according to an embodiment of the present invention.

    [0062] In FIGs. 3A, 3B, and 3C, solid arrows denote electromagnetic fields emitted from loops and dotted lines denote changes in an electromagnetic field emitted from the EI pen.

    [0063] Referring to FIG. 3A, when the EI pen approaches the loop unit, current flows through the first sub-loop unit to determine the X-axis coordinate of the EI pen. Meanwhile, the second sub-loop unit senses electromagnetic changes to determine the Y-axis coordinate of the EI pen. When the EI pen initially approaches, current flows through all loops X1, X2, and X3 of the first sub-loop unit, and then the EI pen receives an induced electromagnetic field from the first sub-loop unit and emits the received electromagnetic field. Each of loops Y1, Y2, and Y3 of the second sub-loop unit senses an electromagnetic change from the EI pen. The loops Y1, Y2, and Y3 of the second sub-loop unit sense electromagnetic changes in a predetermined order. As described herein above, the loops Y1, Y2, and Y3 of the second sub-loop unit may be grouped into a predetermined number of groups and sense electromagnetic changes on a group basis. The electromagnetic sensing apparatus determines a maximum signal loop Y2 with a sensing signal having a maximum magnitude from among the loops.

    [0064] Referring to FIG. 3B, the first sub-loop unit senses electromagnetic changes while current flows through the second sub-loop unit. Meanwhile, the electromagnetic sensing apparatus may provide current only through the maximum signal loop Y2 among the loops of the second sub-loop unit.

    [0065] The EI pen receives an electromagnetic field induced from the maximum signal loop Y2 and outputs the induced electromagnetic field. The loops X1, X2, and X3 of the first sub-loop unit sense electromagnetic changes from the EI pen and the electromagnetic sensing apparatus determines a maximum signal loop X2 from among the loops X1, X2, and X3 of the first sub-loop.

    [0066] Referring to FIG. 3C, the second sub-loop unit senses electromagnetic changes while current flows through the first sub-loop unit. Meanwhile, the electromagnetic sensing apparatus provides current only through the maximum signal loop X2 of the first sub-loop unit. Subsequently, the electromagnetic sensing apparatus determines the time-series coordinates of the EI pen by providing current only through maximum signal loops

    [0067] If the location of the EI pen is changed, the electromagnetic sensing apparatus senses an electromagnetic change by changing a sensing group. For example, if the current maximum signal loop is Y3, the electromagnetic sensing apparatus compares a sensing signal from the loop Y1 with a sensing signal from the loop Y3. If the sensing signal from the loop Y1 is stronger than the sensing signal from the loop Y3, the electromagnetic sensing apparatus shifts the sensing group to the loop Y1. The same operation applies to determining a location with respect to the X axis, and these operations may be repeated until no electromagnetic change is detected from the EI pen.

    [0068] FIG. 4 is a flowchart illustrating a method for controlling an electromagnetic sensing apparatus according to an embodiment of the present invention. In the present example, the electromagnetic sensing apparatus illustrated in FIG. 4 includes first and second sub-loop units that intersect perpendicularly with each other.

    [0069] Referring to FIG. 4, the electromagnetic sensing apparatus provides current through the first sub-loop unit and controls the second sub-loop unit to sense electromagnetic changes, in step S410. After a predetermined time period, the electromagnetic sensing apparatus provides current through the second sub-loop unit and controls the first sub-loop unit to sense electromagnetic changes, in step S420. The above operations are repeated until no electromagnetic change is sensed from the EI pen, in step S430. In other words, the electromagnetic sensing apparatus controls the first sub-loop unit to alternate between current reception and electromagnetic change sensing. At the same time, the electromagnetic sensing apparatus controls the second sub-loop unit to alternate between current reception and electromagnetic change sensing, alternately with the first sub-loop unit at a predetermined time interval.

    [0070] Each of the first and second sub-loop units includes a plurality of loops. At least two of the plurality of loops in each of the first and second sub-loop units, respectively, may sense electromagnetic changes simultaneously. More specifically, the electromagnetic sensing apparatus may group the loops of a sub-loop unit into a predetermined number of groups and control the loops to sense electromagnetic changes on a group basis, rather than controlling the loops to individually sense electromagnetic changes.

    [0071] Each of the first and second sub-loop units in the electromagnetic sensing apparatus includes a plurality of loops. Providing current through the second sub-loop unit, such as in step S420, may involve determining a first maximum signal loop having a maximum sensing signal in the second sub-loop unit that senses electromagnetic changes and flowing current only through the first maximum signal loop after a predetermined time period.

    [0072] After providing current through the second sub-loop unit, such as in step S420, current flows through the first sub-loop unit again and the second sub-loop unit is controlled to sense electromagnetic changes. In this case, current may flow only through the first maximum signal loop during a predetermined time period and a second maximum sensing loop having a maximum sensing signal may be determined in the other sub-loop unit that does not include the first maximum signal loop in the step of flowing current through the first sub-loop unit again. In addition, while current is flowing only through the second maximum signal loop, sensing signals are measured only from a subset of the loops that include the first maximum signal loop in the sub-loop unit that senses electromagnetic changes, during a predetermined time period. A sensing point is determined using signals from the first and second maximum signal loops and their adjacent loops.

    [0073] FIG. 5 is a flowchart illustrating a method for controlling an electromagnetic sensing apparatus according to another embodiment of the present invention.

    [0074] Referring to FIG. 5, the electromagnetic sensing apparatus provides current through the first sub-loop unit, in step S501. At the same time, the electromagnetic sensing apparatus uses the second sub-loop unit as a sensing loop, in step S502. The electromagnetic sensing apparatus determines whether a predetermined time period has elapsed, in step S503. Upon expiration of the predetermined time period, the electromagnetic sensing apparatus determines a first maximum signal loop having a maximum sensing signal from among the loops of the second sub-loop unit, in step S504. The electromagnetic sensing apparatus provides current only through the first maximum signal loop in step S505 and uses the first sub-loop unit as a sensing loop, in step S506. The electromagnetic sensing apparatus determines whether a predetermined time period has elapsed, in step S507. Upon expiration of the predetermined time period, the electromagnetic sensing apparatus determines a second maximum signal loop having a maximum sensing signal from among the loops of the first sub-loop unit, in step S508. The electromagnetic sensing apparatus provides current only through the second maximum signal loop, in step S509 and uses the second sub-loop unit as a sensing loop, in step S510. The above operations are repeated until no electromagnetic change is sensed from the EI pen, in step S511.

    [0075] FIG. 6 is a flowchart illustrating a method for controlling an electromagnetic sensing apparatus according to further another embodiment of the present invention.

    [0076] Referring to FIG. 6, the electromagnetic sensing apparatus detects the position of the EI pen, in step S601. Detection of an initial position of the EI pen is performed as described hereinabove in detail, and therefore, a further description of this process is omitted for conciseness.

    [0077] The electromagnetic sensing apparatus receives sensing signals from loops corresponding to the position of the EI pen (i.e., from loops adjacent to the first and second maximum signal loops) and compares the received sensing signals, in step S602.

    [0078] The electromagnetic sensing apparatus changes a sensing range based on the result of the comparison, in step S603. For example, if a sensing signal from a loop to the left of the maximum signal loop of the first sub-loop unit is stronger than a sensing signal from a loop to the right of the maximum signal loop of the first sub-loop unit, the electromagnetic sensing apparatus may shifts the entire sensing range to the left. The electromagnetic sensing apparatus subsequently repeats the same operations with respect to the second sub-loop unit. Thus, if a sensing signal from an adjacent loop is stronger than a sensing signal from the maximum signal loop of the second sub-loop unit, the electromagnetic sensing apparatus shifts the entire sensing range in a direction the loop having the stronger sensing signal is located.

    [0079] The electromagnetic sensing apparatus may detects the position of the EI pen again based on the changed sensing range, in step S604 and repeats the above-described procedure until the electromagnetic change sensing ends, that is, no electromagnetic change is sensed from the EI pen, in step S605.

    [0080] As is apparent from the above description of embodiments of the present invention, since current flows through only a subset of at least two loops from among a plurality of loops of a loop unit in certain exemplary embodiments, power consumption is reduced and the size of an IC for a driver can also be decreased.

    [0081] In addition, electromagnetic changes are sensed using sensing loops on a group basis rather than using loops individually in certain exemplary embodiments. Consequently, a total sensing time can be reduced. The resulting increase in the number of sensing operations performed over a period of time increases an SNR.

    [0082] When a sensing signal is degraded due to a high-resistance sensing loop, the sensing signal can be measured as many times as allowed by a decrease in sensing time achieved through simultaneous measurements, thereby maintaining SNR. If a predetermined number of sensing signals are measured at the same time, a driving voltage can be increased instead of increasing the number of measurements, thereby increasing SNR. In addition, circuitry can be simplified by implementing a transmitter in a voltage-driven fashion.

    [0083] An EI pen in certain exemplary embodiments of the present invention may include a condenser and a loop. As pressure applied to the tip of the EI pen changes capacity or inductance, the frequency of an electromagnetic field emitted from the EI pen changes. Therefore, a change in the pressure applied to the pen tip can be acquired based on the frequency change of a sensing signal. Meanwhile, the frequency change of a sensing signal may be detected as a phase change in a phase detector. The pressure of the pen tip can be calculated by monitoring the phase value of a sensing signal.

    [0084] It will be appreciated that embodiments of the present invention can be realized in the form of hardware, software or a combination of hardware and software. Any such software may be stored in the form of volatile or nonvolatile storage such as, for example, a storage device like a ROM, whether erasable or rewritable or not, or in the form of memory such as, for example, RAM, memory chips, device or integrated circuits or on an optically or magnetically readable medium such as, for example, a CD, DVD, magnetic disk or magnetic tape or the like.

    [0085] It will be appreciated that the storage devices and storage media are embodiments of machine-readable storage that are suitable for storing a program or programs comprising instructions that, when executed, implement embodiments of the present invention. Accordingly, embodiments provide a program comprising code for implementing apparatus or a method as claimed in any one of the claims of this specification and a machine-readable storage storing such a program. Still further, such programs may be conveyed electronically via any medium such as a communication signal carried over a wired or wireless connection and embodiments suitably encompass the same.

    [0086] While the present invention has been particularly shown and described with reference to embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the scope of the present invention as defined by the following claims.


    Claims

    1. An electromagnetic sensing apparatus for measuring, using electromagnetic induction, a position of an object with respect to a device including the electromagnetic sensing apparatus, the apparatus comprising:

    a loop unit including a first sub-loop unit (111) and a second sub-loop unit (112); and

    a controller (120) configured to control the first sub-loop unit (111) to receive a current for generating an electromagnetic field transmitted to the object and the second sub-loop unit (112) to sense an electromagnetic change generated based on the position of the object during a first time period and control the second sub-loop unit (112) to receive a current for generating an electromagnetic field transmitted to the object and the first sub-loop unit to sense an electromagnetic change generated based on the position of the object during a second time period;

    wherein each of the first and the second sub-loop units (111, 112) includes a plurality of loops, and the controller (120) is further configured to select a first maximum signal loop having a sensing signal, generated by the electromagnetic change, with a maximum magnitude among the plurality of the loops of the second sub-loop unit during the first time period and to provide the current only through the first maximum signal loop during the second time period.


     
    2. The electromagnetic sensing apparatus of claim 1, wherein the controller (120) is further configured to alternately control at least two loops in each of the first sub-loop unit (111) and the second sub-loop unit (112) to sense the electromagnetic change.
     
    3. The electromagnetic sensing apparatus of claim 1, further comprising:

    a driver (230) configured to apply a current to the loop unit; and

    a switch (220) configured to alternately output the current received from the driver to the first sub-loop unit and the second sub-loop unit during the first time period and the second time period.


     
    4. The electromagnetic sensing apparatus of claim 3, further comprising a signal processor (250) configured to process the sensing signal induced by the electromagnetic change sensed by the loop unit,
    wherein the controller (120) is further configured to control the switch (220) to alternately connect the signal processor (250) to the first sub-loop unit and the second sub-loop unit during the first time period and the second time period.
     
    5. The electromagnetic sensing apparatus of claim 1, wherein while providing the current through the second maximum signal loop during a third time period, the controller (120) is configured to measure sensing signals from at least two loops including the first maximum signal loop of the second sub-loop unit to sense an electromagnetic change.
     
    6. The electromagnetic sensing apparatus of claim 1, wherein the controller (120) is further configured to determine the sensing point corresponding to the position of the object based on sensing signals from the first maximum signal loop and the second maximum signal loop and loops adjacent to the first and second maximum signal loops.
     
    7. A method for controlling an electromagnetic sensing apparatus including first and second sub-loop units (111, 112) for measuring, by electromagnetic induction, a position of an object with respect to a device including the electromagnetic sensing apparatus, the method comprising:

    receiving, by the first sub-loop unit (111), a current for generating an electromagnetic field transmitted to the object and sensing, by the second sub-loop unit (112), an electromagnetic change generated based on the position of the object during a first time period;

    receiving, by the second sub-loop unit (112), a current for generating an electromagnetic field transmitted to the object and sensing, by the first sub-loop unit (111), an electromagnetic change generated based on the position of the object during a second time period;

    wherein each of the first and second sub-loop units includes a plurality of loops, and wherein sensing the electromagnetic change by the second sub-loop unit (112) during the first time period comprises selecting a first maximum signal loop having a sensing signal, generated by the electromagnetic change, with a maximum magnitude in the second sub-loop unit (112); and

    wherein receiving the current by the second sub-loop unit (112) during the second time period comprises providing the current only through the first maximum signal loop.


     
    8. The method of claim 7, wherein sensing the electromagnetic change includes simultaneously sensing the electromagnetic change simultaneously by at least two of the plurality of loops in the first sub-loop unit set to sense an electromagnetic change.
     
    9. The method of claim 7, further comprising:
    processing the sensing signal induced by the electromagnetic change.
     
    10. The method of claim 7, wherein sensing the electromagnetic change by the first sub-loop unit (111) comprises selecting a second maximum signal loop having a sensing signal, generated by the electromagnetic change, with a maximum magnitude in the first sub-loop unit (111).
     
    11. The method of claim 10, further comprising determining a sensing point corresponding to the position of the object based on sensing signals from the first maximum signal loop and the second maximum signal loop and loops adjacent to the first and second maximum signal loops.
     


    Ansprüche

    1. Elektromagnetische Erfassungsvorrichtung zum Messen, unter Verwendung von elektromagnetischer Induktion, einer Position eines Objekts in Bezug auf eine Einrichtung, welche die elektromagnetische Erfassungsvorrichtung beinhaltet, wobei die Vorrichtung Folgendes umfasst:

    eine Schleifeneinheit, die eine erste Teilschleifeneinheit (111) und eine zweite Teilschleifeneinheit (112) beinhaltet; und

    eine Steuerung (120), die konfiguriert ist, um die erste Teilschleifeneinheit (111) zum Empfangen eines Stroms zum Erzeugen eines elektromagnetischen Feldes, das an das Objekt übertragen wird, und die zweite Teilschleifeneinheit (112) zum Erfassen einer elektromagnetische Änderung zu steuern, die basierend auf der Position des Objekts während eines ersten Zeitraums erzeugt wird, und die zweite Teilschleifeneinheit (112) zum Empfangen eines Stroms zum Erzeugen eines elektromagnetischen Feldes, das an das Objekt übertragen wird, und die erste Teilschleifeneinheit zum Erfassen einer elektromagnetischen Änderung zu steuern, die basierend auf der Position des Objekts während eines zweiten Zeitraums erzeugt wird;

    wobei jede von der ersten und der zweiten Teilschleifeneinheit (111, 112) eine Vielzahl von Schleifen beinhaltet und die Steuerung (120) ferner konfiguriert ist, um eine erste maximale Signalschleife mit einem Erfassungssignal auszuwählen, das durch die elektromagnetische Änderung erzeugt wird, mit einer maximalen Größe unter der Vielzahl der Schleifen der zweiten Teilschleifeneinheit während des ersten Zeitraums und um den Strom nur durch die erste maximale Signalschleife während des zweiten Zeitraums bereitzustellen.


     
    2. Elektromagnetische Erfassungsvorrichtung nach Anspruch 1, wobei die Steuerung (120) ferner konfiguriert ist, um abwechselnd zumindest zwei Schleifen in jeder von der ersten Teilschleifeneinheit (111) und der zweiten Teilschleifeneinheit (112) zu steuern, um die elektromagnetische Änderung zu erfassen.
     
    3. Elektromagnetische Erfassungsvorrichtung nach Anspruch 1, ferner umfassend:

    einen Treiber (230), der konfiguriert ist, um einen Strom an die Schleifeneinheit anzulegen; und

    einen Schalter (220), der konfiguriert ist, um den Strom, der von dem Treiber empfangen wird, abwechselnd an die erste Teilschleifeneinheit und die zweite Teilschleifeneinheit während des ersten Zeitraums und des zweiten Zeitraums auszugeben.


     
    4. Elektromagnetische Erfassungsvorrichtung nach Anspruch 3, ferner umfassend einen Signalprozessor (250), der konfiguriert ist, um das Erfassungssignal zu verarbeiten, das durch die elektromagnetische Änderung induziert wird, die durch die Schleifeneinheit erfasst wird,
    wobei die Steuerung (120) ferner konfiguriert ist, um den Schalter (220) zu steuern, um den Signalprozessor (250) abwechselnd mit der ersten Teilschleifeneinheit und der zweiten Teilschleifeneinheit während des ersten Zeitraums und des zweiten Zeitraums zu verbinden.
     
    5. Elektromagnetische Erfassungsvorrichtung nach Anspruch 1, wobei die Steuerung (120) während des Bereitstellens des Stroms durch die zweite maximale Signalschleife während eines dritten Zeitraums konfiguriert ist, um Erfassungssignale von zumindest zwei Schleifen zu messen, einschließlich der ersten maximalen Signalschleife der zweiten Teilschleifeneinheit, um eine elektromagnetische Änderung zu erfassen.
     
    6. Elektromagnetische Erfassungsvorrichtung nach Anspruch 1, wobei die Steuerung (120) ferner konfiguriert ist, um den Erfassungspunkt entsprechend der Position des Objekts basierend auf Erfassungssignalen von der ersten maximalen Signalschleife und der zweiten maximalen Signalschleife und Schleifen benachbart zu der ersten und der zweiten maximalen Signalschleife zu bestimmen.
     
    7. Verfahren zum Steuern einer elektromagnetischen Erfassungsvorrichtung, die eine erste und eine zweite Teilschleifeneinheit (111, 112) beinhaltet, um durch elektromagnetische Induktion eine Position eines Objekts in Bezug auf eine Einrichtung zu messen, welche die elektromagnetische Erfassungsvorrichtung beinhaltet,
    wobei das Verfahren Folgendes umfasst:

    Empfangen, durch die erste Teilschleifeneinheit (111), eines Stroms zum Erzeugen eines elektromagnetischen Feldes, das auf das Objekt übertragen wird, und Erfassen, durch die zweite Teilschleifeneinheit (112), einer elektromagnetischen Änderung, die basierend auf der Position des Objekts während eines ersten Zeitraums erzeugt wird;

    Empfangen, durch die zweite Teilschleifeneinheit (112), eines Stroms zum Erzeugen eines elektromagnetischen Feldes, das auf das Objekt übertragen wird, und Erfassen, durch die erste Teilschleifeneinheit (111), einer elektromagnetischen Änderung, die basierend auf der Position des Objekts während eines zweiten Zeitraums erzeugt wird;

    wobei jede von der ersten und der zweiten Teilschleifeneinheit eine Vielzahl von Schleifen beinhaltet und wobei das Erfassen der elektromagnetischen Änderung durch die zweite Teilschleifeneinheit (112) während des ersten Zeitraums das Auswählen einer ersten maximalen Signalschleife mit einem Erfassungssignal, das durch die elektromagnetische Änderung erzeugt wird, mit einer maximalen Größe in der zweiten Teilschleifeneinheit (112) umfasst; und

    wobei das Empfangen des Stroms durch die zweite Teilschleifeneinheit (112) während des zweiten Zeitraums das Bereitstellen des Stroms nur durch die erste maximale Signalschleife umfasst.


     
    8. Verfahren nach Anspruch 7, wobei das Erfassen der elektromagnetischen Änderung das gleichzeitige Erfassen der elektromagnetischen Änderung gleichzeitig durch zumindest zwei aus der Vielzahl von Schleifen in der ersten Teilschleifeneinheit beinhaltet, die eingestellt ist, um eine elektromagnetische Änderung zu erfassen.
     
    9. Verfahren nach Anspruch 7, ferner umfassend:
    Verarbeiten des Erfassungssignals, das durch die elektromagnetische Änderung induziert wird.
     
    10. Verfahren nach Anspruch 7, wobei das Erfassen der elektromagnetischen Änderung durch die erste Teilschleifeneinheit (111) das Auswählen einer zweiten maximalen Signalschleife mit einem Erfassungssignal, das durch die elektromagnetische Änderung erzeugt wird, mit einer maximalen Größe in der ersten Teilschleifeneinheit (111) umfasst.
     
    11. Verfahren nach Anspruch 10, ferner umfassend das Bestimmen eines Erfassungspunktes entsprechend der Position des Objekts basierend auf Erfassungssignalen von der ersten maximalen Signalschleife und der zweiten maximalen Signalschleife und Schleifen benachbart zu der ersten und der zweiten maximalen Signalschleife.
     


    Revendications

    1. Appareil de détection électromagnétique destiné à mesurer, à l'aide de l'induction électromagnétique, une position d'un objet par rapport à un dispositif comprenant l'appareil de détection électromagnétique, l'appareil comprenant :

    une unité de boucle comprenant une première unité de sous-boucle (111) et une seconde unité de sous-boucle (112) ; et un dispositif de commande (120) configuré pour commander la première unité de sous-boucle (111) pour recevoir un courant destiné à générer un champ électromagnétique transmis à l'objet et la seconde unité de sous-boucle (112) pour détecter un changement électromagnétique généré sur la base de la position de l'objet durant une première période de temps et commander la seconde unité de sous-boucle (112) pour recevoir un courant destiné à générer un champ électromagnétique transmis à l'objet et la première unité de sous-boucle pour détecter un changement électromagnétique généré sur la base de la position de l'objet durant une deuxième période de temps ;

    chacune des première et seconde unités de sous-boucle (111, 112) comprenant une pluralité de boucles, et ledit dispositif de commande (120) étant en outre conçu pour sélectionner une première boucle de signal maximal possédant un signal de détection, généré par le changement électromagnétique, avec une amplitude maximale parmi la pluralité de boucles de la seconde unité de sous-boucle durant la première période de temps et pour fournir le courant uniquement à travers la première boucle de signal maximal durant la deuxième période de temps.


     
    2. Appareil de détection électromagnétique selon la revendication 1, ledit dispositif de commande (120) étant en outre configuré pour commander en alternance au moins deux boucles dans chacune de la première unité de sous-boucle (111) et de la seconde unité de sous-boucle (112) pour détecter le changement électromagnétique.
     
    3. Appareil de détection électromagnétique selon la revendication 1, comprenant en outre :
    un pilote (230) configuré pour appliquer un courant à l'unité de boucle ; et
    un commutateur (220) configuré pour délivrer alternativement en sortie le courant reçu en provenance du pilote à la première unité de sous-boucle et à la seconde unité de sous-boucle durant la première période de temps et la deuxième période de temps.
     
    4. Appareil de détection électromagnétique selon la revendication 3, comprenant en outre un processeur de signal (250) configuré pour traiter le signal de détection induit par le changement électromagnétique détecté par l'unité de boucle, ledit dispositif de commande (120) étant en outre configuré pour commander le commutateur (220) pour raccorder alternativement le processeur de signal (250) à la première unité de sous-boucle et à la seconde unité de sous-boucle durant la première période de temps et la deuxième période de temps.
     
    5. Appareil de détection électromagnétique selon la revendication 1, tout en fournissant le courant à travers la seconde boucle de signal maximal durant une troisième période de temps, ledit dispositif de commande (120) étant configuré pour mesurer les signaux de détection provenant d'au moins deux boucles comprenant la première boucle de signal maximal de la seconde unité de sous-boucle pour détecter un changement électromagnétique.
     
    6. Appareil de détection électromagnétique selon la revendication 1, ledit dispositif de commande (120) étant en outre configuré pour déterminer le point de détection correspondant à la position de l'objet sur la base des signaux de détection provenant de la première boucle de signal maximal et de la seconde boucle de signal maximal et des boucles adjacentes aux première et seconde boucles de signal maximal.
     
    7. Procédé permettant de commander un appareil de détection électromagnétique comprenant des première et seconde unités de sous-boucle (111, 112) destinées à mesurer, par induction électromagnétique, une position d'un objet par rapport à un dispositif comprenant l'appareil de détection électromagnétique,
    le procédé comprenant :

    la réception, par la première unité de sous-boucle (111), d'un courant destiné à générer un champ électromagnétique transmis à l'objet et détecter, par la seconde unité de sous-boucle (112), un changement électromagnétique généré sur la base de la position de l'objet durant une première période de temps ;

    la réception, par la seconde unité de sous-boucle (112), d'un courant destiné à générer un champ électromagnétique transmis à l'objet et détecter, par la première unité de sous-boucle (111), un changement électromagnétique généré sur la base de la position de l'objet durant une deuxième période de temps ;

    chacune des première et seconde unités de sous-boucle comprenant une pluralité de boucles, et ladite détection du changement électromagnétique par la seconde unité de sous-boucle (112) durant la première période de temps comprenant la sélection d'une première boucle de signal maximal possédant un signal de détection, généré par le changement électromagnétique, avec une amplitude maximale dans la seconde unité de sous-boucle (112) ; et

    ladite réception du courant par la seconde unité de sous-boucle (112) durant la seconde période de temps comprenant la fourniture du courant uniquement à travers la première boucle de signal maximal.


     
    8. Procédé selon la revendication 7, ladite détection du changement électromagnétique comprenant la détection simultanée du changement électromagnétique simultanément par au moins deux de la pluralité de boucles dans la première unité de sous-boucle réglée pour détecter un changement électromagnétique.
     
    9. Procédé selon la revendication 7, comprenant en outre :
    le traitement du signal de détection induit par le changement électromagnétique.
     
    10. Procédé selon la revendication 7, ladite détection du changement électromagnétique par la première unité de sous-boucle (111) comprenant la sélection d'une seconde boucle de signal maximal possédant un signal de détection, généré par le changement électromagnétique, avec une amplitude maximale dans la première unité de sous-boucle (111).
     
    11. Procédé selon la revendication 10, comprenant en outre la détermination d'un point de détection correspondant à la position de l'objet sur la base de signaux de détection provenant de la première boucle de signal maximal et de la seconde boucle de signal maximal et des boucles adjacentes aux première et seconde boucles de signal maximal.
     




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    Cited references

    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description